during hylobatid bipedalism, but the energy-saving capacities.

Study Identifies Energy Efficiency As Reason For …

In the oceans, the Carboniferous is called the Golden Age of Sharks, and ray-finned fish arose to a ubiquity that they have yet to fully relinquish. Ray-finned fish probably prevailed because of their high energy efficiency. Their skeletons and scales were lighter than those of armored and lobe-finned fish, and their increasingly sophisticated and lightweight fins, their efficient tailfin method of propulsion, changes in their skulls, jaws, and new ways to use their lightweight and versatile equipment accompanied and probably led to the rise and subsequent success of ray-finned fish in the Carboniferous and afterward. , which are amoebic protists, rose to prominence for the first time in the Carboniferous. Reefs began to recover, although they did not recover to pre-Devonian conditions; those vast Devonian reefs have not been seen again. did not appear until the . Trilobites steadily declined and nautiloids familiar today, and straight shells became rare. The first , which were ancestral to squids and octopi, first appeared in the early Carboniferous, but some Devonian specimens might qualify. Ammonoids flourished once again, after barely surviving the Devonian Extinction. This essay is only focusing on certain prominent clades, and there are many and . The early Carboniferous, for example, is called the Golden Age of , which are a kind of , which is a phylum that includes starfish. The crinoids had their golden age when the fish that fed on them disappeared in the end-Devonian extinction. Earth’s ecosystems are vastly richer entities than this essay, or essay, can depict.

BIPEDALISM MODEL EVALUATOR : Home ..

In the mid-Miocene cooling’s early stages, beginning about 14 mya, apes were richly spread across Eurasia and were adapted to the hardier diets that less-tropical biomes could provide, and one from Spain 13 mya . It largely lived on the ground and had a relatively upright posture. Its discovery threw previously accepted ideas of ape evolution into disarray. The idea of apes ancestral to humanity living beyond Africa is a recent one, but is gaining acceptance. Important new fossils are found with regularity, as with all areas of paleontology, but the most plentiful funding is for investigating human ancestry. A , with features common to both orangutans and African apes, led to questioning whether some key ape features are ancestral or . One early finding is still highly controversial as to where it fits into the evolutionary tree, as it had ape and monkey features but lived 10 million years after the hypothesized ape/monkey split. The great ape lineages are the subject of considerable controversy today, and the human ancestral tree is regularly shaken up with new findings.

After the , when matter began to coalesce, virtually all mass in the universe was contained in hydrogen atoms, with traces of the next two lightest elements: helium and lithium. According to the , atoms have no mass by themselves, but the field that gives rise to the provides the mass. Gravity attracted hydrogen atoms to each other and, where “clumps” of hydrogen became large enough, the pressure in the clump’s center (a star’s core) became great enough so that the mutual repulsion of the protons in hydrogen nuclei was overcome (like charges repel each other, while opposite charges attract), and the protons fused together. That fusion released a great deal of primordial Big Bang energy, and fusion powers stars.

Why be bipedal? · john hawks weblog

Numerous causes for the evolution of human bipedalism involve freeing the hands for carrying and using tools, in provisoning, changes in climate and environment (from to ) that favored a more elevated eye-position, and to reduce the amount of skin exposed to the tropical sun. It is possible that bipedalism provided a variety of benefits to the hominin species, and scientists have suggested multiple reasons for evolution of human bipedalism. There also is not only question of why were the earliest hominins partially bipedal but also why did hominins become more bipedal over time. For example, the postural feeding hypothesis explains for how earliest hominins became for the benefit of reaching out for food in trees while the savanna-based theory describes how the late hominins that started to settle on the ground became increasingly bipedal.

Jan 06, 2018 · Why be bipedal

See main article: . According to the Savanna-based theory, descended from the trees and adapted to life on the savanna by walking erect on two feet. The theory suggests that early hominids were forced to adapt to bipedal locomotion on the open savanna after they left the trees. This theory is closely related to the knuckle-walking hypothesis, which states that human ancestors used quadrupedal locomotion on the savanna, as evidenced by morphological characteristics found in and forelimbs, and that it is less parsimonious to assume that knuckle walking developed twice in genera Pan and Gorilla instead of evolving it once as synapomorphy for Pan and Gorilla before losing it in Australopithecus. The evolution of an orthograde posture would have been very helpful on a savanna as it would allow the ability to look over tall grasses in order to watch out for predators, or terrestrially hunt and sneak up on prey. It was also suggested in P.E. Wheeler's "The evolution of bipedality and loss of functional body hair in hominids", that a possible advantage of bipedalism in the savanna was reducing the amount of surface area of the body exposed to the sun, helping regulate body temperature. In fact, ’s supports the savanna-based theory by explaining the shrinking of forested areas due to global warming and cooling, which forced animals out into the open grasslands and caused the need for hominids to acquire bipedality.

I know of no more informative contrast between industrial and preindustrial economies than comparing the USA’s North and South on the eve of its Civil War. The North had a vibrant, industrializing economy that quickly became history’s greatest, with its labor nominally free, and the South had a relatively moribund economy based on slave labor. The North used its industrial capacity to grind down the South in a war of attrition, just as . Superior industrial capacity, which is rooted in energy supplies, has won all major wars during the past two centuries. World War I ended when the , and much of the war was devoted to cutting off the other belligerents’ oil supplies. When Germany surrendered, it had one day’s worth of fuel. Japan attacked Pearl Harbor in 1941 only after the , and Germany lost World War II after its , and the Nazis simply ran out of fuel. Cutting off access to hydrocarbons, oil in particular, was the industrial equivalent of starving out the enemy in a siege, or how continually tried to cut off the other's access to wood. Oil has been humanity’s , and explains imperial meddling and warfare in the Middle East. All other factors are irrelevant or of extremely minor importance and are often promoted in an attempt to deceive uninformed observers such as the American public; proximate causes, if not entirely fictional to begin with, in those delusion-inducing analyses.

Although Enlightenment philosophers acknowledged their debt to Newton (the world’s most towering intellectual of his time and one of history’s greatest scientists and mathematicians), he saw nothing improper with the slave trade and in 1720. When machines began reproducing human labor, the abolition of slavery also began, as it made unskilled labor uneconomical. Slavery, particularly the genocidal forms inflicted by Europe, were viable only for situations in which little professional skill was needed. Slavery worked best in mine and plantation work that used illiterate and often-expendable people. What became the USA was unique in the European age of slavery, in that tobacco operations, unlike sugar plantations, had more seasonal labor demands. Moreover, the environment of southeast North America was conducive to long-lived and fertile slaves, so that they could reproduce. Consequently, what became the USA was a , with its large slave population largely bred, not captured. People born into slavery are easier to keep enslaved than those born free, but they had to be kept illiterate and at low skill levels, or else they might desire freedom and obtain it. Late in the American era of slavery, some slaves were taught to read, but generally only one book, which justified slavery: the Bible. All the way to , apologists for slavery used Biblical passages to justify it. Many also justified antebellum slavery with economic arguments, stating that people took better care of something they owned rather than something they rented.

When , there was real economic benefit from their activities, not simply accounting legerdemain, and their was more sustainable. Venetians and Genoese engaged in early instances of a similar process, but it began ascending in earnest as Europe conquered the world. The basic tenet of mercantilism was the acquisition of “treasure” by the mother nation via “trade.” The classic mercantile situation was forcing subjugated people to produce raw material for shipment to the imperial nation for processing. The finished goods would be shipped back to the subjugated people at an inflated price, as the imperial nation slowly milked the subject nation by unfair terms of exchange that they controlled (or sold such cheaply produced goods to other nations). In mercantilist practice, they did not usually dictate how the workforce was organized or how they worked. The intervention was at the market level, by interposing themselves into the process in which producers were enslaved and bled dry by unfair pricing for both raw goods and finished goods. The imperial power had both captive producers and markets for finished goods. Early colonial efforts were largely mercantilist in nature when they were not simply gold rushes.

(equal with Wheeler's thermoregulatory hypothesis) ..

The thermoregulatory model explaining the origin of bipedalism is one of the simplest theories so far advanced, but it is a viable explanation. Dr. Peter Wheeler, a professor of evolutionary biology, proposes that bipedalism raises the amount of body surface area higher above the ground which results in a reduction in heat gain and helps heat dissipation. When a hominid is higher above the ground, the organism accesses more favorable wind speeds and temperatures. During heat seasons, greater wind flow results in a higher heat loss, which makes the organism more comfortable. Also, Wheeler explains that a vertical posture minimizes the direct exposure to the sun whereas quadrupedalism exposes more of the body to direct exposure. Analysis and interpretations of reveal that this hypothesis needs modification to consider that the and environmental of early-stage bipedalism preceded further refinement of bipedalism by the pressure of . This then allowed for the more efficient exploitation of the hotter conditions , rather than the hotter conditions being hypothetically bipedalism's initial stimulus. A feedback mechanism from the advantages of bipedality in hot and open habitats would then in turn make a forest preadaptation solidify as a permanent state.

One hypothesis for human bipedalism is that it evolved as a ..

AB - Bipedalism is a defining feature of the hominin lineage, but the nature and efficiency of early hominin walking remains the focus of much debate. Here, we investigate walking cost in early hominins using experimental data from humans and chimpanzees. We use gait and energetics data from humans, and from chimpanzees walking bipedally and quadrupedally, to test a new model linking locomotor anatomy and posture to walking cost. We then use this model to reconstruct locomotor cost for early, ape-like hominins and for the A.L. 288 Australopithecus afarensis specimen. Results of the model indicate that hind limb length, posture (effective mechanical advantage), and muscle fascicle length contribute nearly equally to differences in walking cost between humans and chimpanzees. Further, relatively small changes in these variables would decrease the cost of bipedalism in an early chimpanzee-like biped below that of quadrupedal apes. Estimates of walking cost in A.L. 288, over a range of hypothetical postures from crouched to fully extended, are below those of quadrupedal apes, but above those of modern humans. These results indicate that walking cost in early hominins was likely similar to or below that of their quadrupedal ape-like forebears, and that by the mid-Pliocene, hominin walking was less costly than that of other apes. This supports the hypothesis that locomotor energy economy was an important evolutionary pressure on hominin bipedalism.